Generally, in order to promptly switch a valve closed state to a valve opened state, a drive circuit of an electromagnetic fuel injection device performs a control of applying a high voltage from a high voltage source to a coil in response to an output of an injection pulse to rapidly raise a current of the coil. Next, a control is performed in which a needle is separated from a valve seat to move toward a fixed core and the applied voltage is changed to a low voltage so that a constant current is supplied to the coil. When the supply of the current to the coil is stopped after the needle collides with the core, the valve opening operation of the needle is delayed and hence a controllable injection amount is limited. Thus, a control is required in which the supply of the current to the coil is stopped before the needle collides with the fixed core and a valve body is controlled in a so-called half-lift condition in which the needle and the valve body move according to a parabolic motion.
As a control method in the condition in which the valve body is driven in a half-lift state, a method disclosed in PTL 1 is particularly known. PTL 1 discloses a method of calculating an integrated value of a drive current flowing in a coil driving a fuel injection valve and calculating an inductance of the driving coil in consideration of a direct current superposition characteristic of the driving coil based on the integrated value. Accordingly, since the inductance is calculated with high accuracy, a lift amount can be highly accurately estimated by estimating the lift amount of the valve body based on the inductance.